1. Field of the Invention
The present invention relates to a navigation apparatus that can provide guidance on branches more properly when a moving object, such as a vehicle, equipped with the navigation apparatus reaches an intersection, a map information storage medium which the navigation apparatus employs, and a method of providing information about areas lying beyond a certain intersection for users more properly.
2. Description of Related Art
A prior art navigation apparatus intended for vehicles as disclosed in Japanese Patent No. 2,924,885 stores the names of a plurality of areas lying along each road outgoing from each intersection to which a vehicle equipped with the navigation apparatus can be headed. Only when there are two consecutive branch points (first and second branch points) that have to be targets for guidance and they are associated with the same name of an area lying beyond the two branch points, the navigation apparatus selects and displays, as a target area lying beyond the first branch point, an area lying beyond the first branch point having the same name as one of areas lying beyond the second branch point.
A problem with such a prior art navigation apparatus constructed as mentioned above is that when a vehicle equipped with the navigation apparatus approaches a place where no consecutive branch points exist, the navigation apparatus selects one of areas lying around the place for guidance without reference to any rules, or provides guidance on all areas lying around the place regardless of a destination set by users, and therefore the navigation apparatus cannot provide guidance on the name of a necessary area lying around the place for users or provides guidance on the name of an unnecessary area lying around the place for users, so that it is difficult for users to select necessary information.
The present invention is proposed to solve the above-mentioned problem, and it is therefore an object of the present invention to provide a navigation apparatus that can select an on-target area lying beyond a certain intersection or a certain branch point and can provide the name of the selected area for guidance, a map affection storage medium which the navigation apparatus employs, and an area information providing method capable of providing information about an on-target area lying beyond a certain intersection or a certain branch point for users.
In accordance with an aspect of the present invention, there is provided a navigation apparatus including a route searching unit for searching for a route from a current position of a moving object to a destination or via point set by an input unit based on map information acquired by a map information acquiring unit, an intersection extraction unit for extracting information about an intersection that is located forward of the moving object along the route and that is a target for guidance from the acquired map information, an area information extraction unit for extracting one or more pieces of area information about one or more areas lying along the route and beyond the intersection from the acquired map information, a comparison unit for comparing specific information included in each of the one or more pieces of area information with either destination information about the destination or via point information about the via point, a selection unit for selecting one piece of area information that is to be a target for guidance based on comparison results obtained by the comparison unit among from the one or more pieces of area information, and an output unit for outputting the selected area information.
As a result, the present invention provides an advantage of being able to provide guidance on an on-target area lying beyond a certain intersection or the like that is a target for guidance.
In accordance with another aspect of the present invention, there is provided a map information storage medium that stores area information including information about a representative point of each of a plurality of areas lying along roads that intersect at each of a plurality of intersections which are targets for guidance.
As a result, the present invention provides an advantage of being able to easily provide area information including information about a location of each of a plurality of areas lying along roads that intersect at a certain intersection that is a target for guidance.
In accordance with a further aspect of the present invention, there is provided a method including the steps of searching for a route from a current position of a moving object to a destination or via point based on acquired map information, extracting information about an intersection that is located forward of the moving object along the route and that is a target for guidance from the acquired map information, extracting one or more pieces of area information about one or more areas lying along the route and beyond the intersection from the acquired map information, comparing specific information included in each of the one or more pieces of area information with destination information about the destination or via point information about the via point, selecting at least one piece of area information that is to be a target for guidance based on comparison results obtained in the comparison step among from the one or more pieces of area information, and outputting the selected area information.
As a result, the present invention provides an advantage of being able to provide guidance on an on-target area lying beyond a certain intersection or the like that is a target for guidance.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.